This invention relates to a ski structure, and more specifically, it is concerned with isotropic reinforcement rib members which extend between the top surface and the opposing bottom or running surface of the ski which permit two primary ski characteristics to be controllably increased dependent upon the type and quantity of reinforcement material utilized.
The continued popularity of downhill skiing has focused attention on the structure of skis to produce a ski that provides greater responsiveness to the improved skiing techniques being employed by skiers today and the increased speed being achieved as a result of these techniques. This continued popularity has caused the materials used in skis to be changed in the efforts to develop higher performance skis at lower manufacturing costs. Skis have been made solely from wood, composite wood-plastic materials, as well as entirely from plastics. Skis made entirely from metal have also been manufactured, as well as incorporating metal into composite wood-plastic skis or into all plastic skis. In particular, the advent of high performance wood-fiberglass and fiberglass-plastic foam skis has intensified the skiing industry's efforts to solve the problem of providing a ski constructed of quality materials which provides increased ski return rates, increased designable natural frequency, increased designable torsional rigidity, and a bottom steel running edge with increased impact resistance.
Different approaches have been taken in attempt to solve these problems as higher performance skis have evolved in the ski industry. Initially, skis were made with just a wooden core. For some time, a core made of plastic material, such as plastic foam or urethane, placed within a honeycomb structure formed from aluminum, has been employed. However, because of the higher performance nature of today's skis, these composite skis are subjected to greater flexibility strains which the aforementioned constructions have either failed to withstand or have provided skis which produce a dead sensation to the user. None of the aforementioned structures have provided skis which balance the considerations of high material costs, difficulty in contouring the skis during manufacture and other problems and inefficiencies that occur during the molding and assembly processes employed in the manufacture of snow skis today.
Additionally, to date the prior art ski designs have been ineffective at designing center spring ski constants comparable to those obtained in the high performance racing skis into the recreational skis of preselected lengths used by the general public while increasing the rate of return or snap. Recreational skis typically have been characterized as soft or flexible because they enabled skiers to make turns at relatively slow speeds. The stiff or non-flexible skis, typically utilized for alpine racing, are more difficult to get into a turn at the slower speeds normally achieved by recreational skiers. An increased rate of return or snap in a ski facilitates recovering from a turn. Thus, the optimum design for a recreational ski is one that is soft or flexible with a high rate of return that permits a recreational skier to initiate a turn at a relatively low speed by virtue of the ski's designed flexibility, but which also imparts a livelier feel to the skier and helps the ski recover from the turn because of a designably increased rate of return or snap comparable to that found in racing skis of greater stiffness and higher center spring constants.
The foregoing problems are solved in the design of the present invention by providing structure in a snow ski which creates an increased rate of return and a more lively feel at a lower overall spring constant to provide a quicker responding ski or one that provides a faster change in turning direction.